Bicyclo compound, method for producing pentacene and a film thereof using the same, and method for producing bicyclo compound

ABSTRACT

A method for producing highly purified fused aromatic ring compounds with high yield by a simpler method. A method for producing a fused aromatic ring compound comprising irradiating the bicyclo compound containing at least one bicyclo ring represented by formula (1) in a molecule with light to detach a leaving group X from a residual part to form an aromatic ring: 
                         
wherein R 1  and R 3  each denotes a group to form an aromatic ring or a heteroaromatic ring which may be substituted, together with a group to which each thereof is bonded; R 2  and R 4  each denotes a hydrogen atom, an alkyl group, an alkoxy group, an ester group or a phenyl group; and X is a leaving group, which denotes a carbonyl group or —N═.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of U.S. application Ser. No. 10/543,382,filed Jul. 26, 2005 now U.S. Pat. No. 7,601,478, which is a U.S.national stage of International Application No. PCT/JP2004/002498, filedMar. 1, 2004, and which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to novel bicyclo compounds, a method forproducing highly purified fused aromatic compounds using the same. Thepresent invention further relates to a method for forming a film of sucha highly purified fused aromatic compound.

BACKGROUND ART

In the electronics field, non-linear optical properties, conductivityand semiconductivity of various organic compounds have been attractingattention, and various devices using organic substances have beenactively developed. Phthalocyanine compounds, porphyrin compounds, fusedpolycyclic aromatic ring compounds, such as polyacenes and pyrene,arylamine compounds, bisazo pigments and the like, are known as typicalexamples of organic semiconductor compounds. Properties, such asnon-linear optical properties, electrical conductivity andsemiconductivity, which are required for using these compounds asorganic materials to form devices, largely depend on crystallinity andorientation of each of the materials, and it is important to use highlypurified materials in order to fully exploit these properties. However,high purification of these materials has been difficult, because many ofcompounds having an extended π-conjugated system are susceptible tooxidation in air.

Fused aromatic ring compounds represented by pentacene have beenreceiving attention in recent years for their electrical conductivity,semiconductivity etc. However, it is very difficult to obtain pentaceneof high purity due to its low solubility.

Particularly, it is necessary to form thin films of pentacene in orderto use it for various devices, but thin film preparation using a vacuumprocess etc. increases the production cost. In recent years, there hasbeen developed a method for producing pentacene from a pentaceneprecursor using the reverse Diels-Alder reaction as a key reaction(WILLEY-VCH Verlag GmbH, “Advanced Materials”, Vol. 11, No. 6, p.480-483, 1999). However, the conversion to pentacene requires ahigh-temperature treatment of 170° C. or above and freed high masscomponents must be removed under a reduced pressure. Conversion topentacene at a low temperature is also reported (“Journal of AmericanChemical Society”, Vol. 124, p. 8812-8813, American Chemical Society,2002), but there is a problem in the stability of the soluble precursorof pentacene.

DISCLOSURE OF THE INVENTION

Conventionally, highly purified fused aromatic ring compounds aredifficult to obtain due to the low solubility thereof. Particularly,acene compounds have a low solubility and are difficult to purify, so amethod for producing highly purified compounds has been demanded.Further, a vacuum process such as vacuum evaporation or sputtering isrequired for preparation of a film of a fused aromatic ring compound, soa simpler method has been demanded.

The present invention was made to solve these problems, and it is anobject of the present invention to provide new bicyclo compounds to beused for obtaining highly purified fused aromatic ring compounds.

It is another object of the present invention to provide a method forproducing a highly purified fused aromatic ring compound with high yieldby a method simpler than the conventional ones.

It is a further object of the present invention to provide a method foreasily forming films of highly purified fused aromatic ring compounds.

The inventors have found new bicyclo compounds having a specificstructure. Specifically, they found that a leaving group is detachedfrom such a bicyclo compound by light irradiation, and an aromatic ringis formed in the residual part to form a fused aromatic ring compound.Further, they found that the film of a bicyclo compound of a specificstructure can easily be converted into a film of a fused aromatic ringcompound by the photodecomposition reaction. The present invention hasbeen made based on these findings.

Namely, the present invention provides a bicyclo compound containing atleast one bicyclo ring represented by formula (1) in a molecule:

wherein R₁ and R₃ each denotes a group to form an aromatic ring or aheteroaromatic ring which may be substituted, together with a group towhich each thereof is bonded; R₂ and R₄ each denotes a hydrogen atom, analkyl group, an alkoxy group, an ester group or a phenyl group; and X isa leaving group denoting a carbonyl group or —N═.

Further, the present invention provides a bicyclo compound representedby formula (1a):

denotes an aromatic ring or a heteroaromatic ring which may besubstituted or not; a, b and c each denotes an integer of 1 to 4; ddenotes an integer of 0 to 4; R₃₁, R₃₂ and R₃₃ each denotes at least onehydrogen atom, alkyl group, alkoxy group, ester group, aryl group,aralkyl group, phenoxy group, cyano group, nitro group or halogen atom,which may be the same or different; and X is a leaving group denoting acarbonyl group or —N═.

Further, the present invention provides a method for producing a fusedaromatic ring compound by irradiating the above bicyclo compound withlight to detach a leaving group X from the residual part to form anaromatic ring.

Further, the present invention provides a method for forming a film of afused aromatic ring compound by irradiating a film of the above bicyclocompound with light to detach a leaving group X from the residual partto form an aromatic ring.

Further, the present invention provides a method for forming a patternedfilm of a fused aromatic ring compound by writing a pattern on a film ofthe above bicyclo compound by light irradiation to detach a leavinggroup X from a residual part to form an aromatic ring.

Further, the present invention provides a method for producing apentacene compound by photolytically decomposing6,13-ethanopentacene-6,13-dione represented by formula (2):

wherein R₂ and R₄ each denotes a hydrogen atom, an alkyl group, analkoxy group, an ester group or a phenyl group; and R₅ to R₁₂ eachdenotes a hydrogen atom, an alkyl group, an alkoxy group, an aryl group,an aralkyl group, a phenoxy group, a cyano group, a nitro group, anester group or a halogen atom, which may be the same or different.

Further, the present invention provides a method for forming a film of apentacene compound by irradiating a film of6,13-ethanopentacene-6,13-dione represented by formula (2) with light.

Further, the present invention provides a method for forming a patternedfilm of a pentacene compound by writing a pattern on a film of6,13-ethanopentacene-6,13-dione represented by formula (2) by lightirradiation.

The present invention also provides new bicyclo compounds usable forobtaining highly purified fused aromatic ring compounds.

Further, the present invention provides a method for producing highlypurified fused aromatic ring compounds with high yield by a simplermethod than conventional methods.

Further, the present invention provides a method for easily formingfilms of highly purified fused aromatic ring compounds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a mass spectrum of compound (6) in Example 1;

FIG. 2 shows a proton NMR spectrum (270 MHz) of compound (6) in Example1;

FIG. 3 shows a carbon 13 NMR of compound (6) in Example 1;

FIG. 4 shows an IR spectrum (KBr pellet method) of compound (6) inExample 1; and

FIG. 5 shows a UV-VIS absorption spectrum of compound (6) in Example 1.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention is described in detail.

The present invention provides a method by which a fused aromatic ringcompound having a low solubility can be produced simply and with highpurity and a method by which a film of the fused aromatic ring compoundhaving a low solubility can be easily formed, using a new bicyclocompound.

The bicyclo compound of the present invention is characterized by havingat least one bicyclo ring represented by formula (1):

In formula (1), R₁ and R₃ each denotes a group to form an aromatic ringor a heteroaromatic ring which may be substituted, together with a groupto which each thereof is bonded.

The aromatic ring or heteroaromatic ring includes benzene ring, anaphthalene ring, an anthracene ring, a pyridine ring, a pyrrole ring ora thiophene ring; and the substituent includes an alkyl group such asmethyl, ethyl or propyl, an aryl group such as phenyl or naphthyl, anaralkyl group such as benzyl or phenethyl, an alkoxy group such asmethoxy or ethoxy, a phenoxy group, a carboxyl group, an ester group, acyano group, a nitro group or a halogen atom such as fluorine, chlorine,bromine or iodine.

R₂ and R₄ each denote a hydrogen atom, an alkyl group such as methyl,ethyl or propyl, an alkoxy group such as methoxy or ethoxy, an estergroup or a phenyl group.

X is a leaving group denoting a carbonyl group or —N═. Further, X-Xpreferably is —CO—CO— or —N═N-group.

Further, the present invention provides a method for producing a fusedaromatic ring compound utilizing the formation of an aromatic ring by aresidual part by irradiating the compound of formula (1) with light todetach the leaving group X from the residual part.

Further, the present invention provides a method for forming a film of afused aromatic ring compound utilizing the formation of an aromatic ringby a residual part by irradiating the compound of formula (1) with lightto detach the leaving group x from the residual part.

The bicyclo compound of formula (1) is irradiated with light to releasetwo molecules of carbon monoxide or nitrogen gas as a leaving group, toallow the residual part to form an aromatic ring, thereby beingconverted to a fused aromatic ring compound.

Here, the wavelength of the light with which the compound of formula (1)is irradiated may be within the absorption wavelength range of thecompound of formula (1), preferably in a longer wavelength range. Alight source can be selected includes from a tungsten lamp, a halogenlamp, a metal halide lamp, a sodium lamp, a xenon lamp, a high-pressuremercury-vapor lamp, a low-pressure mercury-vapor lamp, various laserlight and the like.

Further, the light source to be used is preferably a light source havinga light emission intensity of 300 W or more. Too weak intensity maycause side reaction.

The reaction can provide a fused aromatic ring compound when thecompound of formula (1) is dissolved or suspended in a solvent, and canform a film of a fused aromatic ring compound when the compound offormula (1) is in a film state such as a coating film or an evaporatedfilm.

The solvent for the reaction in which light irradiation is performedincludes methanol, ethanol, butanol, acetone, methyl ethyl ketone,methyl isobutyl ketone, cyclohexanone, hexane, heptane, cyclohexane,tetrahydrofuran, dioxane, diethyl ether, isopropyl ether, dibutyl ether,toluene, xylene, 1,2-dimethoxy ethane, chloroform, ethylene chloride,dimethyl sulfoxide, N-methylpyrrolidone, chlorobenzene, dichlorobenzene,trichlorobenzene or the like.

The reaction temperature of the light irradiation reaction may beselected in a wide range considering properties such as stability andsolubility of the solvent capable of dissolving the compound of formula(1). Preferably, the reaction temperature is in a range from the boilingpoint to the freezing point of the solvent. Further, the solvent ispreferably purged with an inert gas. When a film of a wide area isirradiated with light, uniformity of the light irradiation must beconsidered. When irradiation is done through a mask, care must be takenfor close contact between the mask and the film. Further, directpatterning by laser light or the like is possible.

A preferable example of the present invention provides a6,13-ethanopentacene-6,13-dione compound represented by formula (2):

wherein R₂ and R₄ each denotes a hydrogen atom, an alkyl group such asmethyl, ethyl or propyl, an alkoxy group such as methoxy or ethoxy, anester group or a phenyl group.

R₅ to R₁₂ each denotes a hydrogen atom, an alkyl group such as methyl,ethyl or propyl, an alkoxy group such as methoxy or ethoxy, an arylgroup such as phenyl or naphthyl, an aralkyl group such as benzyl orphenethyl, a phenoxy group, a cyano group, a nitro group, an ester groupor a halogen atom such as fluorine, chlorine, bromine or iodine, whichmay be the same or different.

Further, a method for producing a preferable fused aromatic ringcompound using a compound of formula (2) is to irradiate6,13-ethanopentacene-6,13-dione represented by formula (2) with light torelease two molecules of carbon monoxide being a leaving group, thusproduce pentacene as shown by reaction scheme (3):

A method for forming a preferable film of a fused aromatic ring compoundusing a compound of formula (2) is to irradiate a film of6,13-ethanopentacene-6,13-dione represented by formula (2) with light torelease two molecules of carbon monoxide being a leaving group, thusforming a film of pentacene as represented by reaction scheme (3).

Further, a method for forming a preferably patterned film of a fusedaromatic ring compound using a compound of formula (2) is to directlywrite a pattern on a film of 6,13-ethanopentacene-6,13-dione representedby formula (2) with light to release two molecules of carbon monoxidebeing a leaving group, thus forming a patterned film of pentacene.

A typical synthetic route of the bicyclo compound of the presentinvention is shown below with an example synthesis of6,13-ethanopentacene-6,13-dione, a compound example (6).

The synthetic route comprises the steps as shown by reaction scheme (4).

Namely, a tetraene compound (1) reacts with two molecules of benzyne (2)by addition to produce an adduct (3); the adduct (3) is subjected todehydrogenation reaction to produce an ethylene adduct (4); the compound(4) is oxidized to a diol (5) by an oxidizing agent such as osmiumtetroxide; and the diol (5) is oxidized to a ketone, thereby6,13-ethanopentacene-6,13-dione (6) is provided. The compound (6) iseasily decomposed by light irradiation to pentacene (7). Note that thecompound (6) can also be synthesized by direct addition of ethylene topentacene.

Further, an alternative step shown in the bottom of reaction scheme (4)is also possible. Specifically, the compound (6) can be obtained bytreating a compound (9), which is prepared by adding dichloroethylenecarbonate (8) to pentacene (7), with alkali such as KOH or the like.

An asymmetric bicyclo compound can be obtained according to a routerepresented by reaction scheme (5), in which an equivalent amount ofbenzyne is added to the tetraene compound (1) to obtain a diene (10), towhich benzyne (11) having a different substituent is added, andsubsequently treated in the same manner as in formula (4) to obtain aasymmetric bicyclo compound (15).

Further, a compound (20) which has two bicyclo rings in a molecule canbe synthesized through a route using dibenzyne (16) as shown in reactionscheme (6). As a modification of this reaction, a compound (21) whichhas three bicyclo rings can be synthesized, where dibenzyne (16) and thecompound (10) are reacted in equivalent amounts, an equivalent amount ofdibenzyne (16) is added to the above addition product, and then thecompound (1) is added, which is subsequently reacted with the compound(10) and converted to a ketone via an alcohol in the same manner as informula (4). When dibenzyne (16) and the compound (10) are reacted inthe equivalent amounts, the reaction product is reacted with thecompound (1), then the reaction product is reacted with one-halfequivalent amount of dibenzyne (16) and converted to a ketone via analcohol in the same manner as in formula (4), a compound having fourbicyclo rings can be obtained.

These reaction routes are only a part of examples, and the route toobtain a compound of formula (1) is not limited to them.

The bicyclo compound of the present invention preferably includes acompound represented by formula

denotes an aromatic ring or a heteroaromatic ring which may besubstituted.

In the formula, a, b and c each denotes an integer of 1 to 4, and ddenotes an integer of 0 to 4.

When the aromatic ring or heteroaromatic ring has no substituent, R₃₁,R₃₂ and R₃₃ each denotes a hydrogen atom. When the aromatic ring orheteroaromatic ring has any substituent, R₃₁, R₃₂ and R₃₃ each denotesan alkyl group, an alkoxy group, an ester group, an aryl group, anaralkyl group, a phenoxy group, a cyano group, a nitro group or ahalogen atom, which may be one or more and may be the same or different.

X is a leaving group being a carbonyl group or —N═, with the provisothat X-X is —CO—CO— or —N═N-group.

Examples of bicyclo compounds used in the present invention are shown inTables 1-4. They have one bicyclo ring and a carbonyl group as X.

TABLE 1 Com- pound No.

6

22

23

24

25

26

27

28

TABLE 2 Com- pound No.

29

30

31

32

33

34

35

36

TABLE 3 Com- pound No.

37

38

39

40

41

42

43

44

TABLE 4 Com pound No.

45

46

47

48

49

50

51

TABLE 5 Com- pound No.

52

53

54

55

Example compounds having two or three bicyclo rings are the abovecompound (20) or (21).

Further, the same substituents as R₂, R₄ and R₅ to R₁₂ represented informula (1) can be selected for the compounds (20) and (21).

EXAMPLES

The present invention is not limited to the examples shown below.

Example 1 Synthesis of Compound (3)

5,6,7,8-tetramethylidenebicyclo[2,2,2]oct-2-ene (1) (12 mmol, 1.91 g)and isoamyl nitrite (75 mmol, 10.0 ml) were dissolved in 80 ml of THF(tetrahydrofuran) in a reaction vessel, and refluxed with heating. Asolution in which anthranilic acid (91 mmol, 12.5 g) was dissolved in100 ml of THF was slowly added to the reaction drop-wise using adropping funnel. After the dropping, heating and stirring were continueduntil all raw materials are consumed. After that, an aqueous sodiumhydroxide solution was added to the reaction and stirring was continued.Then the reaction solution was extracted with hexane, and the resultantorganic layer was washed with water and saturated saline, dried overanhydrous sodium sulfate and then concentrated to obtain a crudeproduct. The product was purified by silica gel column chromatography(hexane) to obtain the compound (3). The yield was 2.66 g and 72%.

Molecular formula: C₂₄H₂₀ (308.42)

Shape: White crystal

¹H NMR (CDCl₃) δ=7.10 (4H, s), 6.85 (4H, −J=3.41), 4.29 (2H, t, J=3.41),3.60 (8H, s) [270 MHz]

¹³C NMR (CDCl₃) δ=140.179, 139.254, 134.241, 128.715, 125.858, 54.197,33.164 [67.8 MHz]

Mass spectrum (FAB) m/z: 308 (M+: 22)

Elemental analysis: Calcd (%) C=93.46; H=6.54.

-   -   Found (%) C=93.54; H=6.68.

Synthesis of Compound (4)

The compound (3) (4.02 mmol, 1.24 g) was charged into a reaction vesseland dissolved in 50 ml of chloroform. This solution was added with DDQ(2,3-dichloro-5,6-dicyano-1,4-benzoquinone) (8.04 mmol, 1.80 g) andstirred for 2 hours. A saturated aqueous sodium bicarbonate solution wasadded to the resultant solution and shaken. The resultant organic layerwas washed with water and saturated saline, dried over anhydrous sodiumsulfate and then concentrated under reduced pressure to obtain a crudeproduct. The product was purified by silica gel column chromatography(10% ethyl acetate/hexane) to obtain the compound (4).

Yield 1.20 g (98%)

Molecular formula: C₂₄H₁₆ (304.38)

Melting point: 277.2° C.

Shape: White crystal

¹H NMR (CDCl₃) δ=7.72 (4H, s), 7.69 (4H, m), 7.37 (4H, m), 7.04 (2H, q,J=3.42, 0.98), 5.32 (2H, m) [270 MHz]

¹³C NMR (CDCl₃) δ=142.13, 138.24, 131.68, 127.42, 125.52, 121.23, 50.15[67.8 MHz]

Infrared absorption spectrum (KBr) cm⁻¹: 3054, 2973

Mass spectrum (DIEI) m/z: 304 (M+: 100), 278(13)

Elemental analysis: Calcd(%) C=94.70; H=5.30.

-   -   Found(%) C=94.36; H=5.58.

Synthesis of Compound (5)

NMO (N-methylmorpholine-N-oxide).H₂O (5.60 mmol, 0.78 g) and a stirringbar were put in a 1 L round bottomed flask, and purged with argon.

To the flask, 500 ml of acetone, OsO₄ (0.10 mmol, 5 ml) and the compound(4) (4.11 mmol, 1.25 g) were added in this order, and a stopper wasplugged into the flask. The mixture was vigorously stirred for 32 hourswhile maintained at room temperature. The resultant mixture was addedwith an aqueous solution of Na₂S₂O₄ (0.6 g), stirred for 10 minutes,filtered through Celite, and the mother liquor was extracted with ethylacetate. The resultant organic layer was washed with water and saturatedsaline, dried over anhydrous sodium sulfate and then concentrated underreduced pressure to obtain the compound (5) as a white crystal.

Yield 1.36 g (98%)

Molecular formula: C₂₄H₁₆O₂ (338.40)

Melting point: 299.8° C.

Shape: White crystal

¹H NMR (CDCl₃) δ=7.85 (2H, s), 7.80 (8H, m), 7.43 (4H, m), 4.66 (2H, s),4.22 (2H, s) [270 MHz]

¹³C NMR (CDCl₃) δ=137.349, 135.876, 132.722, 127.574, 125.876, 125.813,125.220, 123.324, 68.411, 51.187 [100.4 MHz]

Infrared absorption spectrum (KBr) cm⁻¹: 3432.67, 370.68 (OH)

Mass spectrum (FAB) m/z: 339 (M+: 4)

Elemental analysis: Calcd(%) C=62.15; H=4.69.

-   -   Found(%) C=62.01; H=4.75.

Synthesis of Compound (6)

Dry DMSO (dimethyl sulfoxide) (132 mmol, 9.4 ml) and 69 ml of dry-CH₂Cl₂were charged into a three-necked reaction vessel under an inert gasatmosphere, and cooled to −60° C. with an acetone/liquid nitrogen bath.To the mixture, 119 mmol (16.5 ml) of anhydrous trifluoroacetic acid wasslowly dropped and stirred for 10 minutes, while maintaining thetemperature of the liquid at −60° C. Then, to the resultant mixture, thecompound (5) (3.81 mmol, 1.29 g) dissolved in a minimum amount of dryDMSO was slowly dropped and stirred for 15 hours. To the mixture,triethylamine (275 mmol, 20.7 ml) was dropped and stirred for 1.5 hours,while maintaining the temperature of the liquid at −60° C. The reactionsolution was slowly poured into 2M HCl (200 ml) and was extracted withCH₂Cl₂. The resultant organic layer was washed with deionized water andsaturated saline, dried over anhydrous sodium sulfate and thenconcentrated under reduced pressure to obtain a crude product, to whichethyl acetate was added. The resultant insoluble material was collectedby filtration to obtain the compound (6).

Yield 0.55 g (43%)

Molecular formula: C₂₄H₁₄O₂ (334.37)

Melting point: 318-323

Shape: Yellow crystal

¹H NMR (CDCl₃) δ=7.94 (4H, s), 7.84 (4H, m) 7.52 (4H, m), 5.31 (2H, s)[270 MHz]

¹³C NMR (CDCl₃) δ=185.165, 133.585, 131.851, 127.862, 127.017, 125.364,60.603 [67.8 MHz]

Infrared absorption spectrum (KBr) cm⁻¹: 1754.90, 1735.62 (C═O)

Mass spectrum (DIEI) m/z: 335 (M+: 4)

Elemental analysis: Calcd(%) C=86.21; H=4.22.

-   -   Found(%) C=86.41; H=4.40.

FIG. 1 shows the mass spectrum of compound (6) in Example 1; FIG. 2shows the proton NMR spectrum (270 MHz) of compound (6) in Example 1;FIG. 3 shows the carbon 13 NMR of compound (6) in Example 1; FIG. 4shows the IR spectrum (KBr pellet method) of compound (6) in Example 1;and FIG. 5 shows the UV-VIS absorption spectrum of compound (6) inExample 1.

Example 2

In a Pyrex (registered trade name) glass cell, 0.005 g of the compound(6) was dissolved in 2 ml of chloroform. The solution was sufficientlydegassed and then irradiated with the metal halide lamp at roomtemperature. Blue crystals were precipitated after several minutes. Theywere collected by filtration to obtain pentacene (7).

Yield 0.004 g (96%)

Molecular formula: C₂₂H₁₄ (278.35)

Shape: Dark blue crystal

Infrared absorption spectrum (KBr) cm⁻¹: 468.14, 731.85, 906.38

Mass spectrum (EI) m/z: 278 (M+: 73)

Elemental analysis: Calcd(%) C=94.93; H=5.07.

-   -   Found(%) C=94.80; H=5.15.

Example 3

A 1% by weight solution of the compound (6) in dichloromethane wasprepared. The solution was spin cast on a glass substrate to form a filmhaving a thickness of 60 nm. The film was irradiated with light for 5minutes by using a xenon lamp. The coating film immediately changed frompale yellow to blue. After the irradiation, the coating film did notcome off even when immersed in chloroform. The UV absorption spectrumrevealed the formation of pentacene.

Example 4

A 1% by weight solution of the compound (6) in dichloromethane wasprepared. The solution was spin cast on a glass substrate to form a filmhaving a thickness of 50 nm. The film was patterned using a dye laser of460 nm. The coating film irradiated with the laser light immediatelychanged from pale yellow to blue. When the coating film was immersed inchloroform after the irradiation, the non-irradiated part dissolved andthe part irradiated with the laser light remained as a blue pattern. TheUV absorption spectrum of this part revealed the formation of pentacene.

Comparative Example 1

A glass tube with a diameter of 5 mm was charged with 0.005 g of thecompound (4) and placed in an oil bath of 250° C. The content in thetube immediately changed to dark blue. After cooling, the content wasthoroughly washed with chloroform and the remained crystal was separatedby filtration. The yield was 0.003 g, 66%.

1. A bicyclo compound represented by general formula:

wherein each of R₂ and R₄ denotes a hydrogen atom, an alkyl group, analkoxy group, an ester group, or a phenyl group; and each of R₅ to R₁₂denotes a hydrogen atom, an alkyl group, an alkoxy group, an aryl group,an aralkyl group, a phenoxy group, a cyano group, a nitro group, anester group, or a halogen atom, which may be the same or different. 2.The bicyclo compound according to claim 1, wherein the bicyclo compoundis represented by formula:


3. A method for producing a film of a pentacene comprising the steps of:writing a pattern by irradiating a film of the bicyclo compoundaccording to claim 1 with light; and removing, from the film of thebicyclo compound irradiated with light, a portion into which the patternwas not written using a liquid, wherein the pattern written in thewriting step is a pentacene film.
 4. A method for producing a bicyclocompound represented by general formula:

wherein each of R₂ and R₄ denotes a hydrogen atom, an alkyl group, analkoxy group, an ester group, or a phenyl group; and each of R₅ to R₁₂denotes a hydrogen atom, an alkyl group, an alkoxy group, an aryl group,an aralkyl group, a phenoxy group, a cyano group, a nitro group, anester group, or a halogen atom, which may be the same or different,comprising the step of oxidizing a diol represented by general formula:


5. A method for producing a bicyclo compound represented by generalformula:

wherein each of R₂ and R₄ denotes a hydrogen atom, an alkyl group, analkoxy group, an ester group, or a phenyl group; and each of R₅ to R₁₂denotes a hydrogen atom, an alkyl group, an alkoxy group, an aryl group,an aralkyl group, a phenoxy group, a cyano group, a nitro group, anester group, or a halogen atom, which may be the same or different,comprising the step of subjecting to an alkali treatment a compoundrepresented by general formula: